1. Field of the Invention
The present disclosure generally relates to earthquake resisting apparatuses, and more particularly to an earthquake resisting apparatus which is appropriate for use in an electronic device, such as an image forming device, at a time of installation of the electronic device.
2. Description of the Related Art
In recent years, with development of the technology of earthquake-proof building construction, a possibility of collapsing of buildings in a major earthquake (for example, an earthquake with seismic intensity level 6) is decreasing.
For this reason, collapsing of a building due to a major earthquake may be prevented, but comparatively large structures within the building may move or overturn due to the major earthquake. It is predicted that the cases in which damage or injuries are caused due to collision with such moving or overturning structures, or evacuation routes are obstructed by the structures are increasing.
In particular, electrophotographic type image forming devices, such as copiers, printers, facsimiles, and multi-function peripherals, are installed on casters or the like in offices such that the devices are easily movable. In many cases, these devices easily move in case of an earthquake.
In a case of a comparatively large-sized image forming device, after the image forming device is moved on the casters to an installation place, an installation height of the image forming device at the installation place is adjusted using the adjusters. Usually, the casters of the image forming device are raised from the floor after installation. However, in a case of a major earthquake, there is a possibility of movement or overturning of the image forming device. Its outside dimensions and weight are comparatively large and there is a danger that damage or injuries are caused due to collision with the image forming device or evacuation routes are obstructed by the image forming device.
In order to avoid such situations, a disaster prevention person in charge of a building or in charge of each floor of a building is required to take anti-disaster measures for preventing movement and overturning of installation objects within the building.
For example, Japanese Laid-Open Patent Publication No. 09-193939 discloses an overturn preventing instrument which is aimed to prevent movement or overturning of an installation object, as the technology regarding prevention of movement and overturning of installation objects. By this overturn preventing instrument, a bottom surface of the installation object is fixed to the upper parts of skids on a horizontal floor, so that the range of the overturn preventing instrument in contact with the floor is extended from the bottom surface of the installation object. Thereby, overturning of the installation object is prevented.
Moreover, Japanese Laid-Open Patent Publication No. 10-252825 discloses a base isolation structure which includes an elastic body to support a stand leg of an installation object, and this elastic body is arranged in a hole of a free-access floor. Japanese Laid-Open Patent Publication No. 2000-145113 discloses an earthquake resisting device which includes a frame arranged on a base floor, and an installation object is fixed to the frame so that the installation object is installed without damaging the base floor.
Further, Japanese Laid-Open Patent Publication No. 2002-070945 discloses a base isolating device which includes a plate-like load transmitting member slidably arranged on a floor surface, a plurality of device support legs slidably arranged on the load transmitting member, a regulation member which regulates a sliding range of the device support leg on the load transmitting member, and an elastic member which is fixed to the device support leg and arranged in the inside of the regulation member to give repulsive force to movements of the device support leg from a predetermined position in horizontal and vertical directions.
In a case of a minor earthquake, the above-mentioned base isolation device moves horizontally on the load transmitting member, and the vibration of the base isolation device is attenuated by the friction of the support leg and the load transmitting member and by elastic deformation of the elastic member. In a case of a major earthquake, the above-mentioned base isolation device moves further and the range of elastic deformation of the elastic member is exceeded. The support leg is directly regulated by the regulation member. The movement of the base isolation device at this time is transmitted to the load transmitting member, and the load transmitting member starts sliding on the floor. Therefore, the base isolation device attenuates the vibration by the friction between the load transmitting member and the floor.
Japanese Laid-Open Patent Publication No. 2009-112399 discloses a movement prevention instrument which connects a floor and a device to prevent movement of the device. A bottom plate of this movement prevention instrument is formed of an adhesive damping material having adhesion and vibration damping properties, and this adhesive damping material is attached to the floor so that the movement prevention instrument is installed.
In a case of the overturn preventing instrument of Japanese Laid-Open Patent Publication No. 09-193939, the overturning of the installation object due to earthquakes is effectively prevented. However, the movement of the installation object due to earthquakes cannot be prevented. For example, when iron is used as the material of the skid, the coefficient of static friction between the overturn preventing instrument and the concrete floor is approximately 0.4. If a major earthquake whose seismic intensity level is 6 or more (horizontal acceleration of approximately 800 Gal) takes place, the acceleration of 0.8 g is applied to the installation object. At this time, the frictional force derived from the coefficient of static friction (0.4) is smaller than the force derived from the horizontal acceleration (0.8 g), and the installation object easily moves. Hence, there may be a danger that the moving installation object collides with people or obstructs evacuation routes.
In addition, in the case of Japanese Laid-Open Patent Publication No. 09-193939, the installation object is directly attached to the skid. The overturn preventing instrument should not be used for electronic devices which require a level surface adjustment in a case of installation. Further, the skid is designed to extend outward from the bottom surface of the installation object, and there is also a danger that a user stumbles over the skid.
In the case of the base isolation structure of Japanese Laid-Open Patent Publication No. 10-252825, it is aimed at preventing movement or overturning of the installation object. However, it is necessary to carry out construction work to perforate the hole in the floor and to embed the elastic body and the screw in the hole. Hence, the base isolation structure costs time and effort for such construction work. There are many kinds of floors, and it is difficult to prepare the base isolation structure in advance for the respective floors. The construction work appropriate for each floor must be performed individually. Hence, the construction work will become complicated and the cost will be increased.
In the case of Japanese Laid-Open Patent Publication No. 10-252825, relocation of an installation object is difficult. For example, if the material of a new floor at a relocation place is different from the material of the floor where the installation object is currently installed, the relocation of the installation object cannot be performed. Even if the material of a new floor at a relocation place is the same as the material of the floor where the installation object is currently installed, it is necessary to carry out the construction work at the relocation place, which costs time and effort which are the same as those of the first installation. Further, in the case of Japanese Laid-Open Patent Publication No. 10-252825, the weight of the installation object is supported by the elastic body and the casters. If the installation object is a heavy-weight device, there is a possibility that the device is partially depressed and the initial attitude of the device cannot be maintained.
In the case of Japanese Laid-Open Patent Publication No. 2000-145113, the installation object can be installed on the base floor without damaging the base floor. However, the frame of the earthquake resisting device is disposed on the base floor, and if the base floor is a concrete floor, the earthquake resisting device cannot be used. In addition, in a case of a major earthquake, the frame may be moved to the base floor. No measures for preventing movement of the frame to the floor are present.
Similar to the disclosure of Japanese Laid-Open Patent Publication No. 09-193939, the disclosure of Japanese Laid-Open Patent Publication No. 2002-070945 is effective to prevent the overturning of the installation object due to earthquakes, but it cannot prevent the movement of the installation object due to earthquakes. Namely, when a large quake arises, transmission of the quake is attenuated by slipping between the load transmitting member and the floor surface, and the installation object can easily move. Hence, there may be a danger that the moving installation object collides with people or obstructs evacuation routes.
In a case of the movement prevention instrument of Japanese Laid-Open Patent Publication No. 2009-112399, it is possible to prevent movement and overturning of a device. However, it is necessary to stick the adhesive damping material (gel sheet) having the adhesion property to the floor surface. If the need for relocation of the movement prevention instrument arises, it is necessary to remove the existing adhesive damping material and prepare a new adhesive damping material. This is troublesome and the cost will be increased.
Further, in a case of a large-sized or heavy-weight installation object, it is necessary to use a plate having a large surface area or a high rigidity as a soleplate of the installation object. If the soleplate is stuck on the floor using an adhesive sheet material, it is difficult to gradually remove the adhesive sheet material from an end thereof. However, it is necessary to tear off the adhesive sheet material at a time, and the difficulty of the removal of the adhesive sheet material arises.
Japanese Laid-Open Patent Publication No. 2010-180926 discloses an earthquake-proof fixing method using a pressure sensitive adhesive sheet. In this method, an adhesive sheet is disposed beneath a supporting portion of an installation object, and a tapped hole for removal is formed in the supporting portion to vertically penetrate the supporting portion. When the installation object is removed from the floor, a bolt for removal is screwed into the tapped hole for removal and the adhesive sheet is removed from the floor by lifting the supporting portion from the floor. However, when a soleplate having a large surface area and a high rigidity is used, it is difficult to rotate the bolt for removal, and the floor surface may be damaged because a strong force is exerted on the floor surface.
In addition, in the case of Japanese Laid-Open Patent Publication No. 2009-112399, the normal free access floor is put on the support member in the building floor, and it is necessary to fix the free access floor to the building floor. Therefore, the installation position is limited. For example, the installation object must be installed directly on a concrete floor.